Control mechanism for compressor valves



Dec. 25, L. l CO| |N5 CONTROL MECHANISM FOR COMPRESSOR VALVES Filed Feb. 26, 1951 INVEN TOR. esef L Cc//f'ms @aww A TTORNE Y.

Patented Dec. 25, 1934 UNITED STATES CONTROL ME'CHANISM FOR COMPRESSOR' v VALVES p Lester L. Collins, Franklin, Pa., assignor to Chicago Pneumatic Tool Company, New York, vN. Y., a corporation of New Jersey Application February 26, 1931, Serial No. 518,406

" 4 claims. (01.137-15'6) This invention relates to mechanism for pumping and compressing gaseous iluids. More particularly it concerns control apparatus for the valves of such mechanism whereby partial or 5 total unloading of the same may be conveniently elected.

One object of the invention is to mount the control apparatus upon or as a part of the closure for the valve chamber. Another object is to make the control apparatus conveniently accessible from the exterior of the pump or compressor without removing the closure and Without disturbing the mounting of the valve. Another object is to vent one 'side of the control apparatus so that the same may be used upon the high pressure side of a compressor. A further object is to eliminate the danger of leakage of uid from the lifter actuating chamber to the intake side of a compressor. A still further object is the provision of a valve which will operate in the clearance pocket of the high pressure side of a variable capacity compressor. Still another object is to arrange for the convenient lubrication of the control apparatus. Other objects will be apparent from the detailed description which follows.

In order to illustrate the invention, one concrete embodiment thereof is shown in the accompanying drawing, the single figure of which shows the cover plate and control elements in vertical section and indicates in broken outline the manner in which the same is mounted in a compressor Cylinder and its relation to a valve assembly.

In the embodiment of the invention chosen for the purpose of illustration the inner and outer Walls a, b of a compressor cylinder A are indicated, the inner Wall having a stepped opening C therethrough in which an inlet valve assembly D of conventional plate type is mounted and retained in place by the usual holding members d. To give access to valve chamber e for the insertion and removal of valve assembly D, the opening f is provided in outer cylinder wall a. The valve lifter G is mounted upon valve assembly D to engage the plate valves of the latter and to hold them open when the compressor cylinder is partially or entirely unloaded. Since the elements heretofore mentioned may be wholly conventional, or of any suitable or desired type, they are indicated in the drawing in broken outline merely for the purpose of showing the general combination and arrangement, and further description thereof is accordingly omitted.

The control apparatus by which valve lifter G may be actuated is supported over and may form a part of or be supported by the member 'which seals the opening f in the outer wall a of the compressor cylinder. The closure comprises a member l. secured over opening f in any suitable manner as by a series of stud bolts 2. Member l has a lower integral wall la which bulges inwardly Aor downwardly beyond the plane of the member and thus extends into valve chamber e. There is a bore lb in the wall in line with the axis of the valve assembly D and of valve lifter G and the wall is extended in line with this bore to provide a guide cylinder lc of substantial extent. Slidably mounted in guide cylinder 1c and projectable therebeyond is a plunger 3 to engage valve lifter G for actuating the same. In spaced relation to wall la is a second wall 4 which bulges in theopposite direction or upwardly from the vplane of closure member l. The chamber between walls lo; and 4 is utilized for fluid pressure means for operatingr plunger 3.5 By preference wall 4 is in the form oi a detachable cap or plate which is secured to member l in any suitable manner as by a series of stud bolts 5. Dividing the space between walls la and 4 is a diaphragm 6 which is securely clamped in place by the inner peripheral face of cap or detachable wall 4, the diaphragm being partially supported by an annular Iiange 1d on member 1. Substantially in line with flange 1d is a head 3a which is secured to or integral With a piston 3b which in turn is secured to or integral with plunger 3 so that pressure fluid admitted through inlet opening 4a in cap or Wall 4 acts through diaphragm 6 and head 3a to move plunger 3 downwardly, thereby actuating valve lifter G. The plunger may be restored to its upper or retracted position by a suitably arranged spring or springs as at h.

To prevent accumulation of pressure beneath the diaphragm 6 especially when the control apparatus is used with an inlet valve on the high pressure side of a compressor and to insure freedom of movement of plunger 3, the piston portion 3b thereof has spaced packing rings 3d. As a further safeguard a vent port '7 extends through member l from the chamber immediately beneath diaphragm 6 to atmosphere. As a further means of sealing piston 3b against leakage of pressure fluid and to insure lubrication at bearing 1b, lubricant feeding passage 8 is provided in member l and the lower wall 1a thereof, which passage extends to bearing 1b intermediate spaced packings 3d. The outer end of the passage may have an alemite iitting 9 through which lubricant may be forcibly fed to bearing 1b.

In the event that it is necessary or desirable to unload the compressor manually, detachable cap or wall member 4 has a threaded bore 4b through which extends a threaded plunger 10 arranged for convenient actuation by a hand wheel 11 and having a head 10a for engagement with head 3a through the interposed diaphragm 6. A packing or gasket ring 12 encircles member 10 above head 10a to be engaged by the latter for making a fluid tight seal when head 10a is in retracted or non-operative position.

The present invention is particularly adapted for use on the high pressure side of two stage compressors by reason of the adequate provision for preventing the accumulation of pressure fluid beneath the diaphragm of the fluid pressure actuating means. The apparatus is also particularly adapted for use with gas compressors in which a different medium from that compressed is used for unloading the compressor, such for example as air. This is due to the fact that there is no possibility of contamination or dilution of the compressed medium by the actuating medium for unloading and due to the fact that escape of the compressed medium is practically eliminated through the long bearing arrangement for 'the plunger or piston and the spaced packing rings thereon and the forceful feeding of lubricant to the space between the rings.

While the invention has been herein shown in what is now considered its preferred form, it is to be understood that the invention is not limited to the specific details thereof, but covers all changes, modifications and adaptations within the scope of the appended claims.

I claim as my invention:

1. In compressor control apparatus, an inlet valve, a chamber in which the valve is mounted, a closure for said chamber, said closure having a bearing, a piston mounted in said bearing and connected to the valve to operate the latter, and

being exposed to pressure in said chamber tending to force the piston outwardly, a second chamber positioned outwardly of said piston and having a movable Wall connected to the latter, said movable wall having an area greater than the effective area of the piston exposed to fluid pressure in the rst chamber whereby the piston may be forced inwardly to operate the valve when the pressure in the second chamber is no greater than the pressure in the valve Chamber.

2. Compressor control apparatus according to claim 1 in vwhich the portion of the piston adjacent the movable wall is surrounded by a chamber maintained at atmospheric pressure irrespective of the pressure in the valve chamber.

3. In compressor control apparatus, a valve chamber, a closure therefor having inner and outer spaced walls providing therebetween a second chamber, said inner wall providing a cylinder, a piston received within said cylinder, fluid pressure actuated means connected to said piston for operating the latter, said means being disposed between said spaced Walls, the space between said inner wall and piston-operating means being vented and disconnected from the valve chamber.

4. In compressor control apparatus, a valve chamber, a closure therefor having inner and outer spaced walls providing therebetween a second chamber, said inner wall providing a cylinder, a piston received within said cylinder, fluid pressure actuated means connected to said piston for operating the latter, said means being disposed between said spaced walls, the space between said inner wall and piston-operating means being vented and disconnected from the valve chamber, the piston having less eiective area than the piston operating means between said walls.

LESTER L. COLLINS. 

